The invention relates a wheel suspension system for the steerable front wheels of a motor vehicle in which the guide rods are fixed at one end to a vehicle body and elastically supported at another end by a wheel support.
Wheel suspension systems are known such as in DT-PS German patent 868,116 wherein the guide rods thereof are arranged to be supported via elastic elements at pivotal points of the wheel supports and at the vehicle body. These elastic elements effect a longitudinal and transverse springiness in relation to circumferential and lateral forces which occur and a definite springiness of the wheel in a pre-determined direction is attainable. Over and above, a softness in the guide rod support at the side of the wheel support occurs through the elastic support of the guide rod, such that the vehicle loses the required precision and line of tracking during load changes.
Therefore, with known wheel suspension systems, compromises in construction must be made regarding the wheel position changes occurring when circumferential and/or lateral forces occur which work against an optimum laying out of the wheel suspension.
Accordingly, it is an object of the present invention to create a wheel suspension of the kind mentioned at the outset which has the maximum possible longitudinal springiness without the presently occurring disadvantages of conventional constructions with regard to lateral tracking movement.
According to a preferred embodiment of the present invention, the above-noted object is obtained through the use of a wheel support which includes a wheel support part or guide element which is guided by the upper guide rod, and a second wheel support part which, together with a wheel support and track rod lever, is guided by the lower guide rod, and wherein the wheel support parts are swingably connected with each other through the use of an elastic member arranged at a distance from the guide rod pivot points and by a link pin which connects the wheel support parts together.
In addition, a further aspect of the present invention provides that the guide element is supported in an elastic sleeve of the second wheel support part which, in the vehicle longitudinal direction, is constructed so as to be more elastic than it is in the vehicle transverse direction. More particularly, in a preferred arrangement, the elastic sleeve is arranged in a tube-like mounting part of the wheel support part and extends throughout the entire clamping length of the guide element within the tube-like mounting part of the wheel support part.
To enable the defined swingability of the wheel support part, the elastic sleeve is provided, in the vehicle longitudinal direction, with flattenings forming recesses with respect to the tube-like mounting part or through the use of elastic sleeves formed of materials of varying elasticity. It is further noted that the swingability of the wheel support part is advantageously obtained according to the invention in such a way that the wheel support part is connected with the guide element in the form of a joint having an axis which extends substantially in the vehicle transverse direction below the wheel center.
Through the use of the present invention elasticities away from the guide rod pivot points are transferred into the wheel support part between the guide rod pivot points, so that definite elastic springiness in the vehicle longitudinal direction is obtained. This elastic longitudinal springiness provides advantages with respect to the effects of circumferential forces occurring at the wheels of the motor vehicle. That is, during a load change such as, during braking, acceleration, deceleration, or coasting, circumferential loads occur which cause a change in the wheel position of conventional supporting arrangements for the wheel guide rods which leads to the wheels being repositioned in the direction a track leads which produces an undesirable understeer, and on the other hand, when driving through a curve side forces occur which cause a wheel supported in a conventional manner to experience a wheel position change in the direction of a track lead producing an undesirable override effect.
In contrast, the elastic longitudinal springiness which is increased relative to that in the vehicle transverse direction, avoids a spanning of the elastic elements in driving through a curve and during braking, such that no deterioration of the comfort results. Additionally, the overtracking changes produced by the changing longitudinal and lateral forces is prevented and the tracking ability of the vehicle is improved. Especially noteworthy are the advantages obtained regarding driving through curves in that since no spanning of the elastic elements occurs, the longitudinal springiness is fully maintained, and during breaking, a definite elastic springiness in the vehicle longitudinal direction in every vehicle condition is assured. In the case of lateral forces, on the other hand, a relatively stiff wheel guide is obtained by the bearing of the guide element which is constructed so as to be less elastic in the vehicle transverse direction than the vehicle longitudinal direction such that only small elastic crush changes are possible.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.